Heterogeneous Architecture Light-Responsive Stiffness-Tunable Magnetic Actuator

Actuators play important roles in various fields due to their high intelligence. However, the present actuators are hard to achieve high load capacity and easy and fast deformation simultaneously. Here, a novel heterostructure magnetic composite material is proposed, which can work as a matrix to create various actuators by easily tailored and magnetized. Initially, a UV-responsive stiffness-tunable polymer (URST-polymer) is developed using in situ encapsulation of reactive double bonds, achieving a modulus increase of up to 15 600 times after stiffening. By introducing NdFeB@PDA particles into URST-polymer, the heterostructure matrix is created through a one-step curing process, which features dual-functional layers: the layer with NdFeB@PDA particles ensures excellent magnetic actuation properties, while the pure polymer layer guarantees effective UV-induced stiffening. Consequently, the light-responsive stiffness-tunable magnetic actuator (LRST-MA) made by a heterostructure matrix demonstrates rapid actuation, bistable states, and high stiffness. The URST layer also imparts excellent shape memory properties due to a special polymer network. Combining those advantages with structural and magnetization design, the matrix can be used in applications such as multi-morphic actuators, variable stiffness grippers, deployable antennas, and emergency robots, which provide a simple and effective strategy for designing actuators.